This issue is caused by Photoshop and the color profiles of your media, which Iconosquare currently doesn't support in their original form.
To avoid this issue, you can save your files on the sRGB format.
To convert an existing design to sRGB, you need to:
- Open your design in Photoshop
- Go to Edit and click Convert to Profile
- Click on the destination space drop down box
- Select the sRGB option
- Click OK
- Save your design